The invention relates to a method of increasing production from a well. More particularly, but not by way of limitation, the invention relates to a method of injecting a gas or fluid into a well annulus in order to increase production from a reservoir.
Many times, in order to produce oil and gas, a well bore is drilled that will intersect a hydrocarbon bearing reservoir. The initial pressure of the reservoir will be quite substantial. The well will be completed to the reservoir, and thereafter, production may be commenced.
Reservoir fluids and gas will be produced during the life of the well. During the course of production, the reservoir will lose some of the pressure which makes it more difficult to lift the produced fluids and gas to the surface. While the reservoir may contain substantial reserves left to be produced, the inability to withdraw the hydrocarbons due to pressure depletion is a common problem faced by operators.
Numerous devices have been devised in order to overcome the problem of pressure depletion in the reservoir. One common method utilized by operators has been to install within the production tubing a series of gas lift mandrels. As is understood by those of ordinary skill in the art, a gas lift valve is introduced into the mandrel. The gas lift valve will allow gas that is placed into the annulus at a high pressure to be communicated with the inner diameter of the production tubing string.
Generally, gas lift is a method of lifting fluid where relatively high pressure gas is used as the lifting medium through a mechanical process. Two types of method are generally used. First, in continuous flow a continuous volume of high pressure gas is introduced into an eductor tube to aerate or lighten the fluid column until reduction of the bottom hole pressure will allow a sufficient differential across the sand face, causing the well to produce the desired rate of flow.
In order to accomplish this, a flow valve is used that will permit the deepest possible one point injection of available gas lift pressure in conjunction with a valve that will act as a changing or variable orifice to regulate gas injected at the surface depending upon tubing pressure.
The second method is referred-to as intermittent flow which involves the expansion of a high pressure gas ascending to a low-pressure outlet. A valve with a large port permits complete volume and pressure expansion control of gas entering into the tubing, thus either regulating lift of the accumulated fluid head above the valve with a maximum velocity to minimize slippage or controlling liquid fall back, fully ejecting it to the tank with minimum gas.
Jet pumps have also been utilized in oil and gas wells in order to produce low pressure wells. For instance, hydraulic jet pumps have been used as a down hole pump for artificial lift applications. An example of this type hydraulic pump is sold by Trico Industries, Inc. under the trade name "Kobe Hydraulic Jet Pumps".
In these types of hydraulic pumps, the pumping action is achieved through energy transfer between two moving streams of fluid. The power fluid at high pressure (low velocity) is converted to a low pressure (high velocity) jet by the nozzle. The pressure at the entrance of the throat becomes lower as the power fluid rate is increased, which is known as the venturi effect. When this pressure becomes lower than the pressure in the suction passageway, fluid is drawn in from the well bore. The suction fluid becomes entrained with the high velocity jet and the pumping action then begins. After mixing in the throat, the combined power fluid and suction fluid is slowed down by the diffuser. Because the velocity is reduced, the pressure increases-rising to a value sufficient to pump the fluid to the surface.
Despite these devices, there is a need for a device to create a zone of low pressure within a tubing and accelerate production from the production reservoir.